104 lines
3.7 KiB
C
104 lines
3.7 KiB
C
/*****************************************************************************
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Copyright (c) 1994, 2018, Oracle and/or its affiliates. All Rights Reserved.
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License, version 2.0, as published by the
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Free Software Foundation.
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This program is also distributed with certain software (including but not
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limited to OpenSSL) that is licensed under separate terms, as designated in a
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particular file or component or in included license documentation. The authors
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of MySQL hereby grant you an additional permission to link the program and
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your derivative works with the separately licensed software that they have
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included with MySQL.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
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for more details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*****************************************************************************/
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/** @file include/ut0rnd.h
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Random numbers and hashing
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Created 1/20/1994 Heikki Tuuri
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***********************************************************************/
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#ifndef ut0rnd_h
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#define ut0rnd_h
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#include "univ.i"
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#include "ut0byte.h"
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/** The 'character code' for end of field or string (used
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in folding records */
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#define UT_END_OF_FIELD 257
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/** The following function generates a series of 'random' ulint integers.
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@return the next 'random' number */
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UNIV_INLINE
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ulint ut_rnd_gen_next_ulint(
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ulint rnd); /*!< in: the previous random number value */
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/** The following function generates 'random' ulint integers which
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enumerate the value space (let there be N of them) of ulint integers
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in a pseudo-random fashion. Note that the same integer is repeated
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always after N calls to the generator.
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@return the 'random' number */
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UNIV_INLINE
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ulint ut_rnd_gen_ulint(void);
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/** Generates a random integer from a given interval.
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@param[in] low low limit; can generate also this value
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@param[in] high high limit; can generate also this value
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@return the 'random' number */
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UNIV_INLINE
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ulint ut_rnd_interval(ulint low, ulint high);
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/** The following function generates a hash value for a ulint integer to a
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hash table of size table_size, which should be a prime or some random number
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to work reliably.
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@param[in] key value to be hashed
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@param[in] table_size hash table size
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@return hash value */
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UNIV_INLINE
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ulint ut_hash_ulint(ulint key, ulint table_size);
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/** Folds a 64-bit integer.
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@return folded value */
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UNIV_INLINE
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ulint ut_fold_ull(ib_uint64_t d) /*!< in: 64-bit integer */
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MY_ATTRIBUTE((const));
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/** Folds a character string ending in the null character.
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@return folded value */
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UNIV_INLINE
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ulint ut_fold_string(const char *str) /*!< in: null-terminated string */
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MY_ATTRIBUTE((warn_unused_result));
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/** Looks for a prime number slightly greater than the given argument.
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The prime is chosen so that it is not near any power of 2.
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@return prime */
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ulint ut_find_prime(ulint n) /*!< in: positive number > 100 */
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MY_ATTRIBUTE((const));
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/** Folds a pair of ulints.
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@return folded value */
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UNIV_INLINE
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ulint ut_fold_ulint_pair(ulint n1, /*!< in: ulint */
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ulint n2) /*!< in: ulint */
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MY_ATTRIBUTE((const));
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/** Folds a binary string.
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@return folded value */
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UNIV_INLINE
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ulint ut_fold_binary(const byte *str, /*!< in: string of bytes */
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ulint len) /*!< in: length */
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MY_ATTRIBUTE((pure));
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#include "ut0rnd.ic"
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#endif
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